Definition Acanthosis nigricans is a disease that causes dark, thick areas on the skin. The areas affected are spread out and the skin is velvety. It is most common in the armpits and other body folds. The disease may be inherited or caused by problems with how the body uses insulin, obesity, some drugs, and cancer.
What is going on in the body? This disease primarily occurs in the armpits, skin folds around the neck and the groin, between the legs, along the ankles, and on the elbows. The outer surface of the skin is affected.
What are the signs and symptoms of the disease? Signs and symptoms are skin that is darker and feels velvety. These areas are often in the folds along the neck, armpits, groin, at the elbow, knuckles, under the breasts, and around the belly button.
What are the causes and risks of the disease? There are many different causes of the disease. It can be inherited. If inherited, it is harmless and is not linked to any other disorders. It can also be caused by:
Addison's disease, which is caused by a deficiency of hormones from the adrenal gland
hypothyroidism, caused by decreased activity of the thyroid gland
Another type is called pseudoacanthosis nigricans. It is a related to obesity. It is often seen in those with darker skin and insulin resistance caused by obesity. The disease can also be caused by some medications. It is associated with high amounts of nicotinic acid (a medication used for high cholesterol, particularly for high triglycerides) and birth control pills.
Another type is malignant acanthosis nigricans. It can be associated with cancers of the genitourinary or gastrointestinal systems.
What can be done to prevent the disease? If the cause of this condition is obesity, losing weight may control the disease. When it is caused by medications or cancer, there is little that can be done to prevent it. Stopping the medication or diagnosing and treating the condition causing the disease may control it.
How is the disease diagnosed? A primary care doctor, dermatologist, or healthcare professional can make the diagnosis. He or she will conduct a physical examination and look at the skin. Any other problems associated with the disease may also be diagnosed.
What are the long-term effects of the disease? Areas of the skin may have chafing. These areas do not become cancerous. The appearance of these chafed spots bothers some people.
What are the risks to others? This is not a contagious disease and cannot be given to someone else.
What are the treatments for the disease? Treating the disease which is causing the condition, such as obesity or cancer, will help control this disease. Treatment may also improve the abnormal skin.
What are the side effects of the treatments? There are usually few side effects to the treatment of skin abnormalities.
What happens after treatment for the disease? If it is determined that the condition is caused by another disease then that disease will need to be treated.
How is the disease monitored? The disease or condition that is causing acanthosis nigricans will need to be monitored.
Author: James Broomfield, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
